The Unified Method Framework (UMF) defines some constraints with regards to the definition and use of roles and role sets. 

The UMF implements a delayed role assignment approach, which means that the assignment of roles to method content elements is NOT done as part of the definition of the method content elements.  In addition, in the UMF, role definitions are intended to be shared.  Thus, in the UMF, the roles and role sets are defined separately from the method content elements they can be assigned to (e.g., work products and tasks), as well as from the assignments themselves.  For information, see Guideline: Delayed Assignment in the UMF.

Roles and role sets may be shared across practices or may be practice-specific and this decision affects what plug-ins their definitions and assignments are placed.

Shared roles and role sets:

• Shared roles and role sets are defined in a Role Definition Base plug-in. 
• Shared roles are assigned to shared role sets in a Role Definition Base plug-in. 
• Shared roles are assigned to tasks and work products in the Assign plug-in associated with the Base plug-in where the element to be assigned to the role (work product or task) is defined. 

Practice-specific roles and role sets:

• Practice-specific roles and role sets are defined in the Practice Assign plug-in.
• Practice-specific roles are assigned to practice-specific role sets in the Practice Assign plug-in. 
• Practice-specific roles are assigned to tasks and work products in the Practice Assign plug-in. 

The benefits to the UMF approach to roles are:

• Roles and role sets can be shared across practices (shared Role Definition plug-ins)
• Alternate role assignments can be defined (provide alternate Assign plug-ins)

Note: If you are developing a method where the role assignments can NEVER change, then late role assignment is overkill and the role assignments can be done directly in Base plug-ins.

For more information on Role Definition and Practice plug-ins, see Concept: Practice Library Plug-In Types.  For more information on Base and Assign plug-ins, see Concept: Practice Library Plug-In Parts.

For an example of a Role Definition Base plug-in, see UMF Role Definition Base Plug-In Example.